Document Feeder Using Gas Flow For Document Separation and Methods of Using and Manufacturing

ABSTRACT

A document feeder includes a feed belt, a vacuum system, a drive system, and a separator arrangement. The feed belt defines multiple openings through the feed belt and the vacuum system provides a vacuum through the openings of the feed belt to draw a top document into contact with the feed belt. The separator arrangement provides a gas flow directed toward at least a first edge region of the top document to separate at least the first edge region of the top document from one or more documents immediately below the top document. Preferably, the separator arrangement utilizes the Coanda effect to separate the top document. The drive system rotates the feed belt.

FIELD

This application is directed to document feeders and methods of making and using the document feeders. The application is also directed to document feeders with a separator arrangement utilizing a gas flow for at least partially separating documents, and methods of making and using the document feeders.

BACKGROUND

Document feeders are useful in a variety of applications including, but not limited to, printing, copying, faxing, collating, scanning, and sorting. One particular challenge of any document feeder is the separation, or singulation, of documents (e.g., sheets of paper, labels, envelopes, and the like) so that only one document is fed at a time. Generally, feeding double or multiple documents is undesirable.

Many document feeders are designed to be used with a variety of different types of documents. Documents can differ in a variety of ways including, but not limited to, differing in weight, caliper, porosity, size, texture, and the like. One mechanism for feeding documents includes a vacuum system that draws a document towards a feed belt. Document feeders that are designed to work with a range of different documents typically include a vacuum system that can pick up and hold the heaviest, thickest, or most dense documents expected for that application. Such a system, however, may work unreliably with lighter, more porous documents because the vacuum may pass through the lighter, thinner, or more porous document and pick up one or more additional documents as well. This can result in the undesirable feeding of two or more documents at the same time. For example, a vacuum designed to lift 100# paper may have tendency to pick up multiple documents of lightweight and more porous 16# paper.

BRIEF SUMMARY

One embodiment is a document feeder having a feed belt, a vacuum system, a drive system, and a separator arrangement. The feed belt defines multiple openings through the feed belt and the vacuum system provides a vacuum through the openings of the feed belt to draw a top document into contact with the feed belt. The separator arrangement provides a gas flow directed toward at least a first edge region of the top document to separate at least the first edge region of the top document from one or more documents immediately below the top document. The drive system rotates the feed belt. Preferably, the gas flow is directed over a convex surface along which the gas can flow from the separator arrangement to the bottom side of the top document. Preferably, the separator arrangement utilizes the Coanda effect to separate the top document.

Another embodiment is a method of feeding documents. The method includes directing a gas flow against a first edge region of a top document to lift at least the first edge region toward a feed belt and separate at least the first edge region of the top document from one or more documents immediately below the top document. The top document is drawn to the feed belt and fed by rotating the feed belt. Preferably, the method utilizes the Coanda effect to separate the top document.

Yet another embodiment is an apparatus that includes the document feeder described above and a receiving device to receive documents from the document feeder. Examples of suitable receiving devices include, but are not limited to, a printer, copier, fax machine, collator, scanner, sorter, or any combination thereof. Preferably, the apparatus utilizes the Coanda effect to separate the top document.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following drawings. In the drawings, like reference numerals refer to like parts throughout the various figures unless otherwise specified.

For a better understanding of the present invention, reference will be made to the following Detailed Description, which is to be read in association with the accompanying drawings, wherein:

FIG. 1 is a schematic side view of one embodiment of a document feeder, according to the invention;

FIG. 2 is a schematic front view of the document feeder of FIG. 1;

FIG. 3 is a schematic side view of another embodiment of a document feeder, according to the invention; and

FIG. 4 is a schematic block diagram of portions of the document feeders of FIGS. 1-3 (dotted lines indicating additional and optional elements of the document feeder of FIG. 3.)

DETAILED DESCRIPTION

This application is directed to document feeders and methods of making and using the document feeders. The application is also directed to document feeders with a separator arrangement utilizing a gas flow for at least partially separating documents, and methods of making and using the document feeders.

A document feeder can use a flow of gas, such as air, to separate at least a portion of the top document from those documents underneath to provide a more reliable mechanism for separation of the documents for individual feeding. For example, the document feeder can use the Coanda effect to direct a portion of the gas flow along a convex surface and underneath at least a portion of the top document to separate that document from those beneath it and direct the document towards a feed belt.

The Coanda effect, also known as the “boundary layer attachment effect” or “the wall-attachment effect,” is the tendency of a steam of fluid (gas or liquid) to flow along a convex surface in contact with the fluid rather than in a straight line. Although the invention is not bound to any particular theory, it is thought that as the fluid moves across the convex surface a certain amount of friction occurs between the fluid and the surface which tends to slow the fluid. This resistance to flow of the fluid can pull the fluid toward the surface.

The use of the Coanda effect (e.g., the flow of a gas along a convex surface) can allow the gas outlet to be placed at a level below the top document so that the separator arrangement providing the gas flow is not in the document path. The gas flow separates or “fluffs” the top document from those below it.

To further facilitate single document feed, the document feeder may also lift at least the leading edge of a feed belt of the document feeder upon receiving the top document. This action moves the feed belt further away from the remaining documents. Once the top document has been fed into the next stage or device, the document feeder is returned to its original position for feeding the next document.

The document feeder can be a stand-alone device or can be incorporated into, or otherwise coupled or attached to, another device, such as a printer, copier, fax machine, collator, scanner, sorter, and the like. The document feeder can, for example, feed documents one-at-a-time to the next stage of larger apparatus. The document feeder may receive documents, for example, from another portion or stage of the apparatus (or a different apparatus), or documents can be provided by a user (e.g., stacked in a tray or other holding arrangement) for feeding.

FIG. 1 is a schematic side view of one embodiment of a document feeder 100 illustrating selected components. The document feeder includes a feed belt 102, a drive system, a vacuum system, and a separator arrangement. The document feeder may include additional or fewer components than those illustrated in FIG. 1.

The drive system can include, for example, a drive motor 162 (FIG. 4), drive rollers 104, and a tension idler 108. The vacuum system can include, for example, a vacuum generator 164 (FIG. 4) and a vacuum plenum 106. The separator arrangement can include, for example, a gas flow generator 166 (FIG. 4—preferably using the Coanda effect), a separator 110 providing a flow of gas, and a convex surface 112 over which gas from the separator 110 flows. FIG. 2 is a schematic front view of the document feeder 100.

The document feeder 100 is designed to remove the top document 118 from a stack of documents 116. The term “document” can refer to, for example, a sheet of any material (such as a sheet of paper, a sheet of labels, a transparency, and the like) as well as envelopes, magazines, booklets, and the like. It will be recognized that the term “document” is not limited to items that contain textual or graphical information. The document may be blank (e.g., a blank sheet of paper.)

Specific implementations of the document feeder 100 can be designed for particular applications and for use with a particular range of documents. This range could be specified using one or more document parameters such as, for example, document size, weight, porosity, caliper, texture, and so forth. Preferably, the document feeder 100 is capable of selecting only the top document 118 from the stack of documents 116 over the entire parameter range expected for the particular application or indicated for use with the document feeder 100.

The feed belt 102 is formed using any suitable material including, but not limited to, cloth or any other fabric, plastic, or rubber. As illustrated in FIG. 2, the feed belt 102 typically has holes 114 through the belt so that a vacuum can be pulled (using the vacuum plenum 106) to draw and hold the top document 118 to the feed belt. These holes are preferably, but not necessarily, the same size. Any arrangement of holes can be used including a single column of holes running the length of the feed belt, as illustrated in FIG. 2. Other arrangements include two or more columns of holes running the length of the feed belt. The size of the holes 114 and the spacing between holes can affect the strength of the vacuum applied to the top document 118. In some embodiments, patterns of larger and smaller holes can be used where more, or less, vacuum is desired.

The feed belt 102 is rotated by the drive system which, in at least some embodiments, includes drive rollers 104, at least one of which is attached to a drive motor 162 (FIG. 4). A tension idler 108 can be used to maintain tension on the feed belt 102. The drive rollers can be rollers, wheels, or any other suitable component for rotating the feed belt. The drive motor is typically coupled to a controller 160 (FIG. 4) that turns the drive motor on and off as needed and optionally regulates the speed of the drive motor and feed belt.

The vacuum plenum 106 can be made using any suitable material including plastic or metal or any combination thereof. The vacuum plenum 106 typically includes one or move vacuum ports 122 and one or more openings 124. A variety of different arrangements can be used to connect the vacuum port(s) with the opening(s). The vacuum port(s) 122 are coupled to a vacuum generator 164 (FIG. 4) to create the vacuum. The openings 122 are generally directed toward the feed belt 102 to provide a vacuum through the holes 114 in the feed belt and draw and hold the top document 118 to the feed belt.

The separator 110 (preferably utilizing the Coanda effect) can be coupled by a conduit 120 to a gas flow generator 166 (FIG. 4), such as a fan, pressurized gas canister, or compressor. Alternatively, the separator may include a fan or other device for generating a flow of gas. The separator provides a gas, such as air, oxygen, nitrogen, or any other gas, through an opening 126 to create a flow 128 of gas. The gas flow 128 creates the separation between documents that allows documents to be fed by the document feeder 100 one at a time.

The flow 128 of gas is directed along the convex surface 112, preferably using the Coanda effect, toward an edge of the documents 118, 116. This gas flow lifts at least one edge of the top document 118 (and possibly other documents) and separates at least a portion of the top document 118 from the remainder of the documents. The gas flow 128 also preferably directs the top document 118 toward the feed belt 102 where it can be attached using the vacuum system. The use of the Coanda effect can allow the separator 110 to be placed below the level of the top document 118, as illustrated in FIG. 1, so that the separator is not in the feed path of the documents.

The flow rate of the gas, the curvature of the convex surface, and the weight, porosity, and size of the document are factors in the ability of the gas flow to separate top document from those documents beneath it. As one example, a 10-15 psi (about 69,000 to 105,000 N) flow can be used with a convex surface having a ¼ to ⅜ inch (about 0.6 to 1 cm) radius.

The flow rate of the gas and the curvature of the convex surface can be selected to obtain a level of separation for the top document. In one example, about 10 documents are separated from each other, with the gap between documents progressively increasing towards the top of the stack.

Preferably, for any specific implementation of the document feeder 100 the gas flow 128 provided by the separator 110 is sufficient to separate the heaviest document expected for use with that implementation. In some embodiments, the gas flow may be constant and fixed. In other embodiments, the gas flow may be alterable or variable. For example, in some embodiments, a user may be requested to designate a document parameter (e.g., weight) range so that the gas flow can be adjusted accordingly. In other embodiments, there can be an automatic sensing apparatus to select the gas flow based on the documents to be fed.

As one example of operation of the document feeder 100, a gas flow is established through the separator 110 and along the convex surface 112 to separate (e.g., “fluff”) at least one edge of the top document 118 from the remainder of the documents 116. A vacuum is established through the vacuum ports 122 and openings 124 of the vacuum plenum 106 so that the top document 118 is held by the feed belt 102. The feed belt 102 is rotated using the drive rollers 104 and drive motor 162 to feed the top document 118 to the next stage or to another machine. It will be recognized that the vacuum may be established prior to, during, or after establishment of the gas flow and that rotation of the feed belt can begin prior to, during, or after establishment of the vacuum and gas flow.

The document feeding process can be performed continuously; feeding one document after another. The document feeding process can also be performed intermittently; feeding one document and then waiting until commanded to feed the next document, or feeding a series of documents and then waiting. During operation, the gas flow and vacuum may be continuously provided and the feed belt may be continuously rotated. Alternatively, one or more of the gas flow, vacuum, and feed belt may be operated in a non-continuous manner. For intermittent operation, it is more likely that one or more of the gas flow, vacuum, and feed belt will be operated in a non-continuous manner.

It will also be recognized that a document feeder can include one or more feed belts 102. When multiple feed belts are used, the feed belts can be spaced apart from one another to interact with different portions of the document. With multiple feed belts, one or more device components, such as one or more of the drive rollers 104, vacuum plenum 106, separator 110, or convex surface 112, can be extended between multiple feed belts. Alternatively, any of these components can be provided separately for each feed belt (or any subcombination of feed belts.) For example, preferably, but not necessarily, each of the feed belts will be operated using the same drive motor.

FIG. 3 illustrates another embodiment of a document feeder 100′ that utilizes the Coanda effect to separate documents. This feeder also includes a lift system for raising at least a leading edge of the feed belt 102 to further reduce the possibility of feeding multiple documents. In operation, once the top document 118 has been attached to the feed belt 102 at least a leading portion of the feed belt 102 is lifted (arrow 130) away from the remaining documents 116. In one embodiment, the feed belt is lifted about ⅛ to ¼ of an inch (about 0.3 to 0.6 cm) away from its original position. When the top document 118 has been fed then the feed belt 102 is returned to its original position for feeding the next document.

In the particular embodiment of FIG. 3, the document feeder has a pivot point 132 on the upper driver roller 104 a. The document feeder includes a mechanism that lifts at least the leading edge of the feed belt 102 using the pivot point 132. The document feeder may include a counterweight to assist in lifting the feed belt (and associated components of the document feeder.)

A variety of methods can be used to activate the lifting mechanism and raise the feed belt. In one embodiment, a sensor can be used to detect when a document has been attached to the feed belt. The sensor then activates the lifting mechanism (such as a piston or lift motor) to begin raising the feed belt 102.

As another example, in the illustrated embodiment of FIG. 3, a lift actuator 134 is coupled to the vacuum plenum 106 by a conduit 136. When the top document 118 attaches to the feed belt the vacuum within the lift actuator 134 increases which results in movement of a piston 138 to lift the feed belt and associated components. As an alternative, the piston 138 may actuate a lift motor. The piston 138 (or optional lift motor) then raises the leading edge of the feed belt 102. Once the top document 118 is released, the vacuum within the lift actuator 134 decreases, at least partially releasing the piston 138 so that the feed belt returns to its original position.

One embodiment of the document feeder also includes a photo sensor (not shown) that is triggered when a document is attached to the feed belt or when the feed belt is lifted. The photo sensor can actuate the drive motor to begin rotating the feed belt. Optionally, the drive motor can be halted when the document is fed, as detected by the photo sensor or by release of the piston 138. In one embodiment, the top document is fed by the document feeder into a pair of pressure rollers that are running at a faster speed than the feed belt.

A variety of different vacuum plenums can be used. The vacuum plenum 106 in the particular illustrated embodiment of FIG. 3 includes two separate vacuum ports 122 a, 122 b. Vacuum port 122 b is coupled to the lift actuator 134 and the last opening 124 a that holds the top document 118 as it is fed. Thus, the vacuum within the lift actuator 134 only drops when the document is fed. Alternatively, the vacuum port can be coupled to two or more openings with the vacuum decreasing as the document is fed and sequentially uncovers the openings.

As indicated above, the document feeder can be operated continuously or intermittently. One example of operation includes attaching the top document 118 to the feed belt 102 using the vacuum system and separator arrangement as described above. This causes the vacuum in the lift actuator 134 to increase raising at least the leading edge of the feed belt 102. Optionally, as the feed belt is raised, a photo sensor is triggered which starts the drive motor and feeds the document. When the document leaves the feed belt 102, the opening 124 a is exposed and the vacuum in the lift actuator 134 drops which results in the feed belt returning to its original position. Optionally, this movement triggers the photo sensor and turns off the drive motor. The document feeder is then ready to feed the next document.

FIG. 4 is a block diagram of one embodiment of a document feeder illustrating the connection of a controller 160 to other portions of the document feeder, such as the drive motor 162, vacuum generator 164, gas flow generator 166, and optional lift actuator 134 or lift motor 168. Any suitable controller can be used including, but not limited to, controllers that utilize microprocessors and the like. The controller 160 can be part of the document feeder or external to the document feeder and coupled to the document feeder by a wireless or wired connection. The controller 160 can be part of a larger device that includes the document feeder. Optionally, the controller 160 can have user-modifiable parameters to modify instructions provided by the controller 160 to other portions of the document feeder.

The above specification, examples and data provide a description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention also resides in the claims hereinafter appended. 

1. A document feeder comprising: a feed belt, the feed belt defining a plurality of openings through the feed belt; a vacuum system configured and arranged to provide a vacuum through the openings of the feed belt to draw a top document into contact with the feed belt; a drive system configured and arranged to rotate the feed belt; and a separator arrangement configured and arranged to provide a gas flow directed toward at least a first edge region of the top document to separate at least the first edge region of the top document from one or more documents immediately below the top document.
 2. The document feeder of claim 1, further comprising a tray configured and arranged to hold a plurality of documents including the top document and the one or more documents immediately below the top document.
 3. The document feeder of claim 1, wherein the separator arrangement is configured and arranged to provide the gas flow against a back side of the top document and the feed belt is configured and arranged to receive a top side of the top document.
 4. The document feeder of claim 1, wherein the separator arrangement comprises an outlet and a surface configured and arranged to direct the gas flow from the outlet towards the top document.
 5. The document feeder of claim 4, wherein the surface is a convex surface along which the gas can flow from the outlet to the bottom side of the top document.
 6. The document feeder of claim 1, wherein the separator arrangement is configured and arranged to provide an air flow as the gas flow.
 7. The document feeder of claim 1, wherein the vacuum system comprises a vacuum generator.
 8. The document feeder of claim 1, further comprising a lift motor configured and arranged to lift at least a leading edge of the feed belt when a document is attached to the feed belt.
 9. The document feeder of claim 8, further comprising a lift actuator coupled to the vacuum system and configured and arranged to activate the lift motor when a document is attached to the feed belt.
 10. The document feeder of claim 8, further comprising a sensor configured and arranged to activate the drive system when the leading edge of the feed belt is lifted
 11. The document feeder of claim 1, wherein the separator arrangement is configured and arranged to utilize the Coanda effect to separate the top document from the one or more documents immediately below the top document.
 12. A method of feeding documents, the method comprising: directing a gas flow against a first edge region of a top document to lift at least the first edge region toward a feed belt and separate at least the first edge region of the top document from one or more documents immediately below the top document; drawing the top document to the feed belt; and feeding the top document by rotating the feed belt.
 13. The method of claim 12, wherein directing a gas flow comprising directing the gas flow against a back side of the first edge region of the top document.
 14. The method of claim 12, wherein directing a gas flow comprises direction the gas flow over a convex surface to the first edge region of the top document.
 15. The method of claim 12, further comprising lifting at least a leading edge of the feed belt after drawing the top document to the feed belt.
 16. The method of claim 15, wherein feeding the document comprises activating a drive system to rotate the feed belt after the leading edge of the feed belt has been lifted.
 17. The method of claim 12, wherein drawing the top document to the feed belt comprises providing a vacuum through one or more holes in the feed belt to draw the top document to the feed belt.
 18. The method of claim 17, further comprising utilizing the vacuum to activate a lift actuator when the top document is drawn to the feed belt.
 19. The method of claim 18, further comprising activating a lift motor when the lift actuator is activated.
 20. An apparatus, comprising: a document feeder comprising a feed belt, the feed belt defining a plurality of openings through the feed belt, a vacuum system configured and arranged to provide a vacuum through the openings of the feed belt to draw a top document into contact with the feed belt, a drive system configured and arranged to rotate the feed belt, and a separator arrangement configured and arranged to provide a gas flow directed toward at least a first edge region of the top document to separate at least the first edge region of the top document from one or more documents immediately below the top document; and a receiving device configured and arranged to receive documents from the document feeder.
 21. The apparatus of claim 20, wherein the apparatus is a printer, copier, fax machine, collator, scanner, sorter, or any combination thereof. 